The Effect of Experimental Changes in Physiological and Psychological Factors on Perception of Exertional Dyspnea in Healthy Individuals

Abstract

Dyspnea is a clinical term for the sensation of shortness of breath. It is a subjective experience perceived and reported by an affected person when referring to a feeling of the unpleasantness and discomfort related to breathing (Epstein, Manning, and Schwartzstein, 1995; Mukerji, 1990). Both healthy subjects and patients with heart and lung disease can experience this sensation, but a key difference is the level of activity at which this sensation becomes particularly troublesome (West et al., 2010). Typically, healthy subjects experience substantial dyspnea during heavy to severe exertion when demands on the cardiorespiratory system are high, e.g. during running, stair climbing or at high altitude (Mukerji, 1990). By contrast, patients with heart and lung disease are likely to experience this sensation during their day to day activities (Hajiro et al., 1999; Simon et al., 1990; Vivodtzev et al., 2006) which may, as a consequence, become more limited as their condition progresses. So, dyspnea becomes an issue of clinical concern, likely indicative of disease, when it occurs at a level of activity in an individual that would not usually cause any difficulty (Mukerji, 1990). Although dyspnea is associated with a wide range of clinical conditions, it is a particularly significant symptom in Chronic Obstructive Pulmonary Disease (COPD) where it has a major impact on exercise capacity and quality of life